Float operated fill valve

ABSTRACT

A fill valve assembly for a toilet tank or the like includes a riser and a head portion that can be vertically adjusted without removal or disassembly of the valve in order to select a precise tank liquid level. Telescoping conduits in the riser are secured in adjusted position by a bayonet latch system including detents assisted by the force applied by pressurized liquid at the inlet to the assembly. A main valve disk is held against a valve seat by pressure in a control chamber in a standby position and is moved to an open position by venting of the control chamber. The valve includes an axial peripheral flange having an enlarged bead portion captured in an annular channel to provide an O-ring type seal against positive and negative pressure while maximizing flexibility of the disk. A lever for controlling a pilot seat for venting the chamber is pivoted between fulcrum flanges and is held by shoulders abutting one of the flanges. The lever is pivoted by a float in a float chamber. A weir and a float controlled valve prevent entry of water into the float chamber in a refill cycle until tank liquid level reaches the selected level to be maintained.

FIELD OF THE INVENTION

This invention relates to valves for controlling the filling of liquidtanks, and more particularly to an improved fill valve responsive to theposition of a float.

DESCRIPTION OF THE PRIOR ART

Many different types of fill valves for controlling the level of liquidin a tank are known. In general such fill valves include position forsensing liquid level in a tank. A float is often employed. A valveoperated in response to the float position permits flow from a liquidsupply to the interior of the tank when the level drops below apredetermined level maintained by the valve. Fill valves of this typeare used in toilet water tanks to maintain the water at a selected leveland to refill the tank following a flush cycle during which the tank isemptied.

Snyder U.S. Pat. No. 1,037,679 discloses a flushing apparatus with avalve 3 controlled by a main float 23 and an auxiliary float 13. Theauxiliary float 13 is a receptacle mounted for limited vertical movementand has an opening normally closed by a flap or check valve 17. When thetank is emptied, the auxiliary receptacle moves down, the flap valve 17opens to permit water to drain from the auxiliary float 13 and the mainfloat 23 moves down to open the valve 3. As the tank fills, theauxiliary float 13 is lifted, water flows over the upper edges of theauxiliary float 13 and the main float 23 is lifted to close the valve 3.

Brandelli U.S. Pat. No. 4,094,327 discloses a telescoping liquid inletconduit assembly that is adjustable to vary the liquid level in a tank.One conduit 32 has peripheral grooves 29. The other conduit 34 has oneor more protrusions 27 that cooperate with grooves 29. Conduit 34 hasaxial slots permitting the conduit wall to flex. A snap fit end capsecures the conduits in a selected position.

Johnson U.S. Pat. No. 4,646,779 discloses an adjustable fill valve witha riser assembly with side by side inlet and outlet portions. Arotatable nut 44 accessible through opening 218 engages rack gear teeth110 on inlet and outlet sections of a valve body 100. When the nut isrotated, the body is raised or lowered.

Johnson U.S. Pat. No. 3,895,645 and Shames et al. U.S. Pat. No.4,562,859 disclose fill valves with valve disks with peripheral upwardlyfacing lip seals surrounding control chambers above the valve disks.

SUMMARY OF THE INVENTION

A primary object of this invention is to provide a fill valve thatmaintains a precise, repeatable and predictable water level in a tanksuch as a toilet tank. Other objects are to provide a fill valvepermitting easy and precise water level adjustment without removing ordisassembling the valve; to provide a fill valve with a valve disksealing arrangement that maximizes disk flexibility while sealingagainst both positive and negative pressures in a control region abovethe disk; to provide a fill valve having a simplified and easilyassembled control lever mounting arrangement; to provide a fill valvewith a vacuum breaker for preventing back siphonage for a tank into awater supply; to provide a fill valve that is highly sensitive to waterlevel changes in a standby condition yet operates abruptly from fullopen to full closed at the conclusion of a refill operation; and toprovide a fill valve that overcomes problems encountered with known fillvalves.

In brief, in accordance with the present invention there is provided afill valve assembly for maintaining a liquid level in a tank including aliquid inlet conduit and a valve having an inlet communicating with theinlet conduit and an outlet communicating with the tank. A float chamberwithin the tank includes a bottom wall. A dam is spaced above the bottomwall permitting liquid communication between the tank and the floatchamber when liquid level in the tank rises to the elevation of the dam.A float is mounted for floating movement between upper and lowerpositions within the float chamber. A lever connected between the floatand the valve opens the valve in response to downward movement of thefloat and closes the valve in response to upward movement of the float.Means is provided for draining the float chamber when the liquid levelin the tank is below the bottom wall. Means is also provided forproviding a flow path in parallel flow relationship with the dam forpermitting liquid communication between the tank and the float chamberwhen the float is in the upper position.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and the above and other objects and advantages may best beunderstood from the following detailed description of the embodiment ofthe invention shown in the accompanying drawings, wherein:

FIG. 1 is a side elevational view of a fill valve constructed inaccordance with the present invention;

FIG. 2 is a front elevational view of the fill valve, taken from theright side of the valve as viewed in FIG. 1, with a portion of the floatchamber broken away;

FIG. 3 is an enlarged sectional view taken along the line 3--3 of FIG.1;

FIG. 4 is an enlarged fragmentary elevational view taken from the line4--4 of FIG. 1 with a portion broken away;

FIG. 5 is an enlarged fragmentary sectional view taken along the line5--5 of FIG. 2;

FIG. 6 is a fragmentary sectional view taken along the line 6--6 of FIG.5;

FIG. 7 is a sectional view taken along the line 7--7 of FIG. 5;

FIG. 8 is a sectional view taken along the line 8--8 of FIG. 5;

FIG. 9 is a fragmentary sectional view taken along the line 9--9 of FIG.5;

FIG. 10 is a fragmentary sectional view taken along the line 10--10 ofFIG. 5;

FIG. 11 is a fragmentary sectional view taken along the line 11--11 ofFIG. 6;

FIG. 12 is an enlarged fragmentary sectional view taken along the line12--12 of FIG. 8;

FIG. 13 is a view similar to a part of FIG. 5 showing portions of afloat controlled valve and a check valve in alternate positions;

FIG. 14 is an enlarged view similar to a part of FIG. 5 showing the fillvalve in an open position and showing the path of liquid flow throughthe fill valve;

FIG. 15 is a fragmentary sectional view taken along the line 15--15 ofFIG. 14;

FIG. 16 is a fragmentary isometric view of the inner end of the controllever of the fill valve;

FIG. 17 is an exploded isometric view of components of the fill valvewith portions broken away;

FIG. 18 is a greatly enlarged fragmentary sectional view of parts of thevalve cup, valve disk and cap of the fill valve;

FIG. 19 is a partly schematic, simplified side elevational view of thefill valve of FIG. 1 installed in a tank and in a standby condition;

FIG. 20 is a view like FIG. 19 showing the fill valve near the beginningof a tank flush cycle;

FIG. 21 is a view like FIG. 20 showing the fill valve at a subsequenttime following the flush cycle when the tank is being refilled; and

FIG. 22 is a view like FIG. 21 showing the fill valve near the end ofthe tank refill operation.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, there is illustrated a fill valveassembly generally designated by the reference character 24 andembodying the features of the present invention. The assembly 24 servesto control the level of liquid in a tank. A fragment of a bottom wall 26of a tank with which the assembly 24 can be used is seen in FIGS. 19-22.For example, the tank may be the flush tank of a toilet. In this case,the assembly 24 maintains the level of water in the tank at apreselected level, and refills the tank to the preselected level afterthe tank is emptied for a flushing operation.

In general, the assembly 24 includes an adjustable riser assembly 28, avalve head portion 30 and a float assembly 32. A liquid inlet port 34located at the bottom of the riser assembly 28 is adapted to beconnected to a source of pressurized liquid such as a household watersupply. Liquid outlet ports 36 disposed within the tank near the bottomof the riser portion 28 admit liquid to the interior of the tank whenliquid flows through the head portion 30. When a decreasing liquid levelis detected by a float 42, a control lever 38 pivots to bring about themovement of a main valve disk 40 from a closed position to an openposition.

Riser assembly 28 includes a vertically extending support 100 and asupply tube 200 and body 300 movable relative to the support 100 forvertical adjustment of the head portion 30 and thereby of the level ofliquid maintained in the tank. A cap 400 overlies the supply tube 200and body 300 and cooperates with the valve disk 40 to define a valvecontrol chamber 43 within the head portion 30. A cover 500 and a floatchamber 600 enclose these components and also enclose the float 42 andthe lever 38 of the float assembly 32. The elements of each structuralcomponent designated by a three digit reference character share thefirst digit in the subsequent detailed description.

Support 100 includes an inlet segment 102 terminating at inlet port 34and having threads 104 for mating with a threaded retention nut 44(FIGS. 17-21). To mount the assembly 24 in position upstanding from thetank bottom wall 26, a sealing gasket 46 is placed against an attachedflange member 106 and the segment 102 is inserted through a hole in wall26. Nut 44 is tightened in place to hold the support 100 with the inletsegment 102 projecting beyond the wall of the tank. A conventionalfitting secured to threads 104 connects a water supply conduit (notshown) to the end of segment 102 to admit water under pressure to theinlet port 34.

Water entering the inlet port 34 flows through a strainer element 48 inorder to remove particles and debris. Above the region of the filterelement 48, the support 100 includes an inlet conduit portion 108surrounded by a concentric outlet conduit portion 110. Portion 108supplies water from the inlet segment 102 to the supply tube 200.Portion 110 directs water supplied from the head portion 30 to slots 112located around the support 100 above the flange member 106 andterminating at outlet ports 36.

Screws 50 extending through the cover 500 and threaded into the body 300hold the cap 400 and supply tube 200 in the assembled position best seenin FIG. 5. The supply tube 200 has a downwardly extending inlet conduit202. The body 300 has a downwardly extending outlet conduit 302surrounding and concentric with the inlet conduit 202. In order topermit vertical adjustment of the head portion 30 to select a desiredtank water level, the conduits 202 and 302 are telescoped with andslidable relative to conduits 108 and 110 respectively. Thus, inletconduit portion 108 and inlet conduit 202 cooperate to provide an inletflow path of variable length. Similarly, the outlet conduit portion 110and the outlet conduit 302 cooperate to provide an outlet flow path ofsimultaneously variable length. A sleeve 114 holds an O-ring seal 52 toprovide sliding leak tight engagement between conduit portion 108 andinlet conduit 202. A labyrinth seal structure 120 minimizes flow downaround the outside of the outlet conduit portion 110.

A desired water level in the tank can be precisely selected by movingthe head portion 30 up or down within the tank. The selected adjustmentis retained by a bayonet locking system that prevents unintentionalmovement of head portion 30 relative to the support 100 and tank bottomwall 26. As seen in FIGS. 3 and 4, four regularly spaced, upwardlyfacing lock flanges 304 are formed on the interior of the outlet conduit302 near its end. Rows of downwardly facing lock teeth 116 are locatedat four locations around the outer surface of the support 100. Becausethe supply and outlet conduits are concentric, the head portion 30 canbe rotated relative to the support 100. When the head portion is turnedcounterclockwise relative to the support 100, the flanges 304 aredisengaged from the teeth 116 and the head portion may be freely raisedand lowered. When the head portion is turned in the opposite direction,each flange 304 enters a space between adjacent teeth 116 and furthervertical movement is prevented.

When a supply of pressurized water is connected to the inlet port 34,there is a pressure drop across the head portion 30. A typical householdsupply pressure in the range of forty-five to sixty pounds per squareinch results in a force in the neighborhood of four pounds continuouslyurging the head portion in an upward direction. This force is used inthe assembly 24 to provide a latching effect in the bayonet lock system.As seen in FIG. 4, the teeth 116 have axially extending detentprojections 118 and the flanges 304 have cooperating detent recesses306. In the locked position the supply pressure continuously forces theprojections 118 into the recesses 306. This force must be overcome bythe user to release the projections 118 from the recesses 306 before thehead assembly can be rotated to move the flanges 302 from engagementwith the teeth 116.

An enlarged upper section 204 of the supply tube 200 is captured betweenthe cap 400 and the body 300. The upper end of the inlet conduit 202terminates in an annular raised valve seat 206 engaged by the main valvedisk 40 in its closed position seen in FIG. 6. A valve cup 54 includesan annular channel 54A in which the radially outer part of the mainvalve disk 40 is retained. Cup 54 also provides an annular valvingsurface 54B surrounding the valve seat 206. As seen in FIGS. 9 and 117,the surface 54B has radially extending flow ports 54C defined by slotsextending from the inner periphery of the cup 54. Preferably the seat206 projects slightly above the surface 54B to provide final shutoff offlow in the valve closed position. The cup 54 may be made of stampedsheet metal or molded plastic, and the flow ports may be of any desiredsize and shape.

The cap 400 (FIG. 5) includes a restrictor pin 402 projecting through ahole in a central hub 40A of the valve disk 40. As seen in FIG. 6,grooves in the pin 402 permit restricted flow from the inlet conduit 202to the control chamber 43 above the valve disk 40. In the standbycondition, pressurized water trapped in the region 43 biases the valvedisk 40 down into its closed position against the valving surface 54Band seat 206. A pilot valve passage or orifice 404 extends from thecontrol chamber 43 to the exterior of the cap 400. When the level in thetank drops below the selected level, lever 38 moves a resilient pilotvalve seat 56 from the closed position (FIG. 5) to the open position(FIG. 14). Pressure within the control chamber drops and inlet pressuremoves the valve disk to its open position. Water then flows from theinlet conduit, radially out across the valve seat 206 and downwardthrough the flow ports 54C in the valving surface 54B.

Water flowing through the valve assembly 24 drops in pressure fromsupply pressure to atmospheric pressure within the tank. The path offlow of water through the assembly 24, indicated by arrows in FIG. 14,is designed to distribute this drop in pressure in order to achievequiet operation and avoid cavitation. The first substantial drop inpressure occurs when water flows through the flow ports 54C into anannular inner chamber 208 in the inlet tube portion 204. The nextpressure reduction occurs when water flows through ports 210 from thechamber 208 to an outer annular chamber 212. Preferably most of thepressure reduction occurs in these two stages. Because each of thesepressure drops results from flow through relatively small ports intorelatively large areas, the frequency of sound resulting from water flowis relatively high and the coupling of sonic energy back into the watersupply system is reduced.

A peripheral lip 54D of the valve cup 54 cooperates with an upstandingannular flange 214 of the supply tube 200 to form an annular portthrough which water flows from the chamber 212 to a vacuum breakerchamber 406 defined within the cap 400. A vacuum breaker valve disk 58is loosely contained in the chamber 406. Vent ports 408 extend from thechamber 406 to the region within the cover 500. Kinetic energy of waterflowing up past the lip 54D moves the disk 58 up to close the vent ports408. When water flow ceases, the disk drops from the vent ports in orderto vent the flow path to atmosphere and prevent back siphonage of waterfrom the tank through the fill valve assembly 24 to the water supplysystem.

A refill port 410 extends from the vacuum breaker chamber 408. Aflexible tube (not shown) may extend from the port 410 to the toilettank overflow pipe to reseal the trap in the fixture in accordance withknown practice. Preferably about twenty percent of the total flowthrough the valve is diverted through the port 410 for refill of thetrap.

Water flows from the vacuum breaker chamber 406 through an annularpassage defined within an outer peripheral wall 216 of the supply tube200. This annular passage leads to an annular cavity 308 defined in theupper portion of the body 300. From this cavity, water flows radiallyinward through an array of vanes 218 (FIG. 11) which impart a swirlingmotion to the flow of water as it enters the outlet conduit 302. Thespinning motion in the outlet conduit stabilizes the flow and promotescomplete purging of air from the flow path when the valve opens. Earlypurging of air has the advantage that the noise of bubbles is masked bythe normal sounds of the flush cycle.

Valve disk 40 includes a flexible annular valving region 40B extendingradially away from the central hub 40A. At the outer periphery of thedisk 40 there is provided an axially extending rim portion 40Cterminating at an enlarged bead portion 40D. The rim and bead 40C and40D are received in the annular channel 54A of the valve cup 54. Whenthe cap 400 is attached with screws 50, acting on the cover 500, adownwardly extending annular flange 412 is also received in the channel54A. The bead 40D is captured between the cup 54 and the flange 412 andfunctions as a partial O-ring seal.

When the pilot orifice 404 is closed by the pilot seat 56, the controlchamber above the valve disk 40 is pressurized at the water supplypressure and the surrounding vacuum breaker chamber 406 is at loweratmospheric pressure. Bead 40D seals this pressure within the controlchamber. When the pilot orifice is opened and the valve disk 40 opens,the pressure in the control chamber drops to atmospheric pressure. Thereis a higher pressure in the vacuum breaker chamber 406 employed tosupply the refill port 410. For example, the pressure reversal may inthe area of ten pounds per square inch. The bead 40D, because itfunctions as an O-ring seal, is able to seal both positive and negativeor this reverse pressure.

Because the enlarged bead 40D is provided on axial rim 40C rather thanat the outer periphery of the valving region 40B, the sealingarrangement does not interfere with flexing of the region 40B. Thevalving region 40B can flex throughout its full radial extent. As aresult, the valve disk 40 can be urged to its fully open position by arelatively small inlet pressure of only a few pounds per square inch.

Lever 38 is pivotally mounted between the cap 400 and the cover 500without the need for a pivot shaft or pin. As seen in FIGS. 15 and 16,the lever is generally U-shaped in cross section. At an outer end thebight of the U is removed to leave the sides as spring arms 38A forattachment to the float 42. At an inner end, the lever includes a hole38B for mounting of the pilot seat 56. At the location of the pivotaxis, a pair of aligned slots 38C are formed at the intersection of thebight and the side walls of the U shape.

The cap 400 includes an upwardly extending fulcrum flange 414. Adownwardly extending fulcrum flange 502 of the cover 500 is aligned withthe flange 414. As seen in FIGS. 14 and 15, the bight of the U isretained between the flanges 414 and 502. There is sufficient clearanceto permit the lever 38 to pivot between its alternate positions seen inFIGS. 5 and 14 around the pivot axis established by fulcrum flanges 414and 502. A pair of shoulders 416 flanking the flange 414 are received inthe slots 38C. Engagement between the shoulders 416 and the slots 38Cretains the lever 38 in position by preventing longitudinal movement ofthe lever and by preventing shifting or pivoting in the plane of thebight of the U shape.

An outer rim 504 of the cover 500 mates with an upper rim 310 of body300. A lower rim 312 of body 300 mates with an outer rim 602 of thefloat chamber 600. The bottom of the float chamber includes a sleeve 604captured against support projections 314 near the top of the outletconduit 302 of the body 300. A vent grid 506 permits free communicationof atmospheric pressure to the interior region surrounded by the chamber600, the body 300 and the cover 500. These elements form a protectedlocation for the float assembly 32 and also suppress noise resultingfrom the flow of water through the assembly 24.

There are three paths for liquid communication between the interior ofthe float chamber 600 and the surrounding tank. One is by way of thesleeve 604. The upper edge of the sleeve 604 has a reduced heightsegment 605 extending between providing a pair of ribs having upperedges 606 located below the upper edge of the rest of the sleeve 604.Edges 606 thus act as weirs or dams. When water in the tank reaches thelevel of weirs 606, it spills over into the float chamber.

Another path for liquid communication is a port 608 in the bottom wallof the float chamber. A floating check ball 60 is held beneath port 608by fingers 610 surrounded by a protective wall 612. When the water levelin the tank is above the bottom wall of the float chamber 600, the ballfloats and blocks the port 608. When water is present in the floatchamber 600 and when the water level in the surrounding tank drops belowthe bottom of the float chamber, the floating ball check 60 drops fromthe port 608 and water can flow from the float chamber.

The third path for liquid to flow between the float chamber and thesurrounding tank is provided by a float controlled port 614 in thebottom wall of the float chamber 600. Port 614 is defined by a tubularwall 616 extending above and below the chamber wall.

Float 42 includes a hollow, open bottom body 42A and an integral supportarm 42B for suspending the float from the outer end of lever 38 withinthe float chamber 600. The upper end of the arm 42B includes projectionsreceived in openings in the spring arms 38A. Air trapped within the body42A causes the float 42 to be buoyant upon the surface of water whenwater is present within the float chamber 600. Within the body 42A is atubular stopper 42C that is aligned with the tubular wall 616 definingthe port 614. Unequal conical tapers are formed on the interfacing endsof stopper 42C and wall 616 to guide the stopper into contact with thewall 616 as the water level in the tank falls (FIG. 13). The stopper 42Ccooperates With the tubular wall 616 to function as a valve closing theport 614 when the float 42 is in its lowermost position within the floatchamber 600.

Operation of the fill valve assembly may be understood with reference tothe partly schematic illustrations in FIGS. 19-22 of sequentialpositions of components of the assembly during a toilet tank flush andrefill cycle. In the standby mode of FIG. 19, the water level ismaintained in the tank at the elevation identified by the referencecharacter T. The float 42 is in its uppermost position and stopper 42Cis spaced above the tubular wall 616 with the result that the floatcontrolled port 614 is open. As a result the water level within thefloat chamber 600 is at the level designated by the reference characterF and this elevation is the same as elevation T. The check ball 60 issubmerged and its buoyancy holds it against the port 608.

Because the float chamber 600 and tank interior freely communicate inthe standby condition by way of the port 614, the float 42 reactsquickly to any change of the tank water level. This sensitivity permitsthe valve assembly to make up for any small leakage from the tank thatcan occur because of normal flush valve seepage or the like. When thewater level is at the selected position determined by adjusting theheight of the head portion 30 and thus the elevation of the weirs 606,the float 42 and lever 38 hold the pilot seat 56 closed upon the pilotorifice 404. Small amounts of leakage can be replaced by pilot flow ofwater past the restrictor pin 402 and through the pilot orifice 404 whenthe float drops slightly, without cycling the main valve disk 40 openand closed. In addition, this sensitivity provides fast response of thevalve assembly to the decreasing water level at the beginning of a flushcycle.

In FIG. 20 the beginning of a flush cycle is shown. When a flush cycleoccurs, the tank is emptied rapidly into the fixture, and the waterlevel within the tank drops abruptly. As seen in FIG. 20, the waterlevel T in the tank and the water level F in the float chamber 600 havedropped to a level approaching the top of the tubular wall 616. Thedescending float 42 pulls the control lever 38 down and pivots the pilotseat 56 away from the pilot orifice 404. Pressure drops within thecontrol chamber 43 above the valve disk 40 and the valve moves to theopen position. Water begins flowing through the valve assembly 24 forrefilling the tank. The flow into the tank through the assembly 24 isslower than the flow from the tank required to flush the fixture and thewater level continues to drop until the flush cycle ends.

Until the float controlled port 614 is closed by the descending floatstopper 42C, the water level decreases simultaneously inside and outsideof the float chamber. Then for a brief interval the tank water leveldrops while the float chamber water level does not change. However, assoon as the tank water level drops below the bottom wall of the floatchamber 600, the floating check ball 60 drops away from the port 608.This permits the remaining water to flow out of the float chamber intothe tank, leaving the float chamber empty.

The water level in the tank continues to fall until the flush cycle iscomplete and the flush valve closes. Then the flow through the valveassembly 24 to the outlet ports 36 begins refilling the tank. At thesame time, flow diverted through the refill port 410 reseals the trap inthe fixture. FIG. 21 illustrates the tank water level T below the floatchamber as the tank is being refilled. The rising water level is belowthe float chamber. The ball check port 608 is open and the floatcontrolled port 614 is closed.

As the water level in the tank rises to the elevation of the bottom wallof the float chamber, the check ball floats against the port 608 andcloses the port. Port 614 continues to be closed by the float stopper42C. The weight of the float 42 overcomes the buoyant effect of water inthe port 614. As a result, water rises around the float chamber whilethe float chamber remains empty. This condition is illustrated in FIG.22. Although the tank water elevation T is well above the bottom of thefloat chamber, the ports 608 and 614 are closed and water cannot enterthe float chamber. Because the float 42 stays in its lowermost position,the main valve disk 40 remains in its fully open position as the waterlevel approaches the selected elevation.

When the rising water level reaches the level of weirs 606 plus theadded height of a meniscus that initially prevents flow over the weirs606, water rushes over the weirs 606 and rapidly fills the float chamberto the selected level. The surface area of water in the tank surroundingthe float chamber 600 is larger than the area of the float chamber. Thusthe water in the tank acts as a reservoir of immediately available waterto fill the float chamber quickly. This causes the float 42 to riseabruptly from the lowermost position of FIG. 22 to the uppermostposition of FIG. 19. The main valve disk 40 accordingly moves quicklyfrom the fully open to the fully closed position and problems associatedwith slow closure and flow throttling are avoided.

The level of water in the tank is precisely adjusted by telescopingmovement of the conduits 202 and 302 relative to the support 100. Thelevel is selected without removing or disassembling the assembly 24 bypushing the head portion down against inlet water pressure to releasethe latch structures 118 and 306, turning the head portion relative tothe support 100 to free the teeth 116 from the flanges 304 and raisingor lowering the head portion 30 as desired. The water level isestablished by the elevation of weirs 606. A visual reference may beprovided on the exterior of the float chamber 600 to aid the user insetting the water level. Once set, the telescoping parts are latchedwith the aid of inlet water pressure, and the level is repeatedprecisely during subsequent refills.

While the invention has been described with reference to details of theembodiments of the invention illustrated in the drawings, these detailsare not intended to limit the scope of the invention as set forth in theappended claims.

I claim:
 1. A fill valve assembly for maintaining a liquid level in atank, said assembly comprising:a liquid inlet conduit; a valve having aninlet communicating with said inlet conduit and an outlet communicatingwith said tank; a float chamber within the tank, said float chamberincluding a bottom wall; a dam spaced above said bottom wall permittingliquid communication between the tank and said float chamber when liquidlevel in the tank rises to the elevation of said dam; a float mountedfor floating movement between upper and lower positions within saidfloat chamber; connecting means connected between said float and saidvalve for opening said valve in response to downward movement of saidfloat and for closing said valve in response to upward movement of saidfloat; means for draining said float chamber when the continuous liquidlevel in the tank is below said bottom wall; and means for providing aflow path in parallel flow relationship with said dam for permittingcontinuous liquid communication between the tank and said float chamberwhenever said float is above said lower position.
 2. A fill valveassembly as claimed in claim 1, said means for draining comprising afloating check ball below a port in said float chamber.
 3. A fill valveassembly as claimed in claim 1, said means for providing a flow pathcomprising a float controlled valve in said float chamber.
 4. A fillvalve assembly as claimed in claim 3, said float controlled valvecomprising a port in the bottom wall of said float chamber and stoppermeans carried by said float for blocking said port.
 5. A fill valve asclaimed in claim 1, said connecting means comprising a lever mounted forpivoting movement.
 6. A liquid level control assembly for maintaining apredetermined liquid level in a tank, said assembly comprising:a supplyconduit extending between a supply of liquid and the tank and a firstvalve in said supply conduit; a float chamber having a bottom walldisposed above the lowermost portion of the tank; a float within saidfloat chamber movable in response to liquid level variations betweenupper and lower positions; connecting means connected between said floatand said first valve for closing said first valve when said float risesto said upper position and for opening said first valve when said floatfalls from said upper position; means providing liquid communicationbetween the tank and said float chamber when liquid in the tank rises toa level spaced above said chamber bottom wall; a drain flow pathextending between the float chamber and the tank and a second valve insaid drain flow path permitting flow from the float chamber to the tankwhen liquid level in the tank is below the level in the chamber; and alevel sensing flow path extending between the float chamber and the tankand a float controlled third valve permitting flow between the tank andsaid float chamber through said level sensing flow path only when saidfloat is above said lower position.
 7. A fill valve assembly formaintaining a selected water level in a toilet water tank, said fillvalve assembly comprising:an inlet port for pressurized water; a supplyconduit connected to said inlet port; a main valve connected to saidsupply conduit; an outlet conduit extending from said main valve to thetank; a float; a float chamber containing said float; a weir permittingwater to spill from the tank into said float chamber only when the waterlevel in the tank is spaced above the bottom of said float chamber; adrain valve in the bottom of said chamber permitting flow from thechamber to the tank only when the level of water in the tank issubstantially below the level in said chamber; and a float controlledvalve in a wall of said chamber permitting direct communication betweenthe tank and the chamber only after a rising water level in said tankreaches the height of said weir.